This invention relates to microscopic imaging of beta particle emissions.
The introduction of a beta emitting radioisotope into a specimen and the observation of how the isotope is subsequently spatially distributed in the specimen serves as a powerful research methodology in biomedical and biochemical research. Presently available methods of observing the radioisotope spatial distribution (RSD) fall principally into two categories: (1) direct detection of the betas (high energy electrons or positrons emitted from the radioisotope nucleus) with spatially sensitive detectors such as proportional wire chambers, scintillators, etc.; (2) beta detection with photographic-like emulsions placed in close proximity to the specimen. Direct detection
methods have the desirable features of typically 10% efficiency and digitally acquired quantitative images of the RSD, but are restricted to spatial resolutions of 1 mm at best. Emulsion techniques are capable of 1-10 micron resolutions, but at an efficiency of 1% or less. The RSD image obtained in this manner typically requires a month exposure time and only results in a visual record of limited quantitative value. When the beta emitting isotope is tritium, the energy of the emitted beta particles is low, making it particularly difficult to produce an RSD image.